TheBigYahi
New Member
I have an NPE-240A that was installed two weeks ago. I have it set for internal intelligent recirculation mode and I've experienced a significant amount of noise being transmitted through my cold water inlet pipe (3/4" copper), but only during recirculation, not normal operation. I can hear this noise two floors away.
- I put the unit into pump test mode (Diagnostics for 5 seconds, select pump, press i) and observed the noise occurs. To me this confirms it's the recirc function, not the rest of the heating functions. Also, observationally it's whisper quiet when running.
- I confirmed there was no air trapped in the pump by opening the red cap (I heard it when it first ran so I'm pretty sure I know what air in the pump sounds like).
- I closed the cold water inlet valve while the pump was running and I observed that the noise went away. The pump is quite quiet when running.
- I loosened the pipe hangers to confirm it wasn't radiating through the structure.
- I confirmed both filters are clean and the internal check valve moves freely.
- I installed an inline check valve on the cold water inlet hoping to replicate the closed water inlet valve, but the noise continues.
- I called Level 2 support and they were quite helpful but ultimately asked me to turn my water pressure down 20 psi and try it for a day. I confirmed that turning the pressure down does not improve the noise.